This invention relates in general to vehicle power steering assemblies and in particular to an anti-lash assembly for use in such a vehicle power steering assembly.
One known power steering assembly for turning steerable wheels of a vehicle includes a ball nut for transmitting force between an axially movable rack member and a power source. For example, the power source may be an electric motor or hydraulic system. Upon actuation of the power source, the ball nut is driven to rotate relative to the rack member and the rotational force of the ball nut is transmitted to the rack member by balls that drive the rack member axially. The axial movement of the rack member by the balls effects turning movement of the steerable wheels.
Turning movement of the steerable wheels is controlled by a driver rotating a steering wheel. Rotating the steering wheel activates the power source. When rotation of the steering wheel is reversed, both the rotational force of the ball nut and a direction of travel for the rack member are reversed. Reversing the direction of travel for the rack member may result in “lash” in the power steering assembly. For example, the lash may occur when a direction of motion for the power steering assembly is reversed and clearances between components of the power steering assembly are taken up before the reversal of motion is complete. Depending upon the amount of any such lash, the lash may be detectable by the driver as a rattle or other similar noise.
Thus, it would be desirable to have a power steering assembly which reduces the lash between the ball nut and the rack member in the vehicle power steering assembly.